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Homework Help: Dynamics Polar Coordinates

  1. Sep 9, 2010 #1
    1. The problem statement, all variables and given/known data

    http://img138.imageshack.us/img138/4317/problem110.jpg [Broken]

    2. Relevant equations

    3. The attempt at a solution

    Really I have no clue where to start on this guy. We did a problem sort of similar to this in class but we were given acceleration so we could use the form of

    Vp = at [tex]\hat{u}[/tex]

    From there we could say that Vp = [tex]\dot{r}[/tex] [tex]\hat{u}[/tex]r + r[tex]\dot{\theta}[/tex][tex]\hat{u}[/tex][tex]\theta[/tex] = at [tex]\hat{u}[/tex]

    I don't see how I could apply this equation in this problem, or really even if it does apply.
    Any hints would be greatly appreciated, just to get a start in the right direction!
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Sep 9, 2010 #2


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    Homework Helper

    Well, it looks interesting anyway!
    I don't know what you mean by Vp . . .
    Initially, r is just d and θ = 0 (the distance and angle from the origin).
    I think finding dr/dt will require knowing r as a function of time so it can be differentiated. I would write out formulas for the x and y position of the the particle as a function of time as in a standard trajectory question, then calculate r and θ from them. There may be shorter ways.
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